As stated by Professor Gred (2013), the chief executive of Diabetes Australia, the epidemic of Type 2 Diabetes in Australia is due to the many contributing factors made prominent by the changes in society’s lifestyle .

Following the 1960s, there were rapid changes in marketing, food availiablity and composition that drove rapid increase in population weight . Due to the changes in the environment people are living in where food is plentiful, affordable and accessible, and thus more people became reliant on processed food and takeway meals. There is an increase in lesisure-time pursuits ( shopping oneline, computer and electronic games, TV) and sedentary jobs which decreased the amount of daily physical activity. It can threfore be seen that the obesity epidemic is a detrimental outcome of the society’s over-consumption of food and insufficent physcial activity (The Conversation, 2012).

The facts presented in this passage are mostly informal such as "apple-shaped body..." (please note the correction). The word "aetiology" is possibly out of place as most people reading this will not understand its implications. It is commendable to improve vocabulary but as it is not a well-used word it should perhaps be replaced by "causes." "Excessive alcohol drinking" would make the sentence flow better if referred to as simply, excessive alcohol or excessive alcohol consumption.

The use of the 'article' (a, an or the) qualifies the meaning quite often and would help improve "that drove the rapid increase in population weight.."

Always read your work back to yourself and look out for words that may have been ommited in error, or tenses that may confuse the reader. Reading back will also allow you to recognize natural pauses so that you can insert commas where necessary. Spelling always authenticates a passage as the reader can see that the writer is serious:

"Due to the changes in the environment, (comma) people are living in areas where food is plentiful, affordable and accessible and thus, (comma) more people are becoming (became) reliant on processed food and takeway meals...."

and

...(shopping online, computer and electronic games, TV) and sedentary jobs which decrease (decreased) the amount of daily physical activity. It can therefore be seen..."

The intention of the passage can sometimes be changed by the use of words and as the "obesity epidemic" itself is not an "outcome," but "obesity" is, consider "...that (the) obesity (epidemic) is a detrimental outcome of (the) society’s over-consumption of food."